Chemistry Exam Past Questions and Answers | JAMB, WAEC and NECO

Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.

• Question 651: The reddish-brown rust on iron roofing sheets consists of Options:
  A) Fe³⁺(H₂O)₆
  B) FeO.H₂O
  C) Fe₂O₃.3H₂O
  D) Fe₃O₄.2H₂O
  Show Answer
  The correct answer is C .
• Question 652: An element, Z froms an anion whose formula is [Z(CN)₆]^y. If Z has an oxidation number of +2, what is the value of y? Options:
  A) - 2
  B) - 3
  C) - 4
  D) - 5
  Show Answer
  The correct answer is C .
• Question 653: An acid and its conjugate base Options:
  A) can neutralise each other to form a salt
  B) differ only by a proton
  C) differ only by the opposite charges they carry
  D) are always neutral substances
  Show Answer
  The correct answer is B .
• Question 654:

  The type of bonding in [Cu(NH${}_3$)${}^4$]${}^{2+}$ is 

  Options:
  A) coordinate
  B) electrovalent
  C) metallic
  D) covalent
  Show Answer
  The correct answer is A .
• Question 655: The type of bonding in {Cu(NH₃)₄}²⁺ is Options:
  A) coordinate
  B) electrovalent
  C) metallic
  D) covalent
  Show Answer
  The correct answer is A .
• Question 656:

  What is the main source of carbon monoxide (CO) in urban areas?

  Options:
  A) Volcanic eruptions
  B) Vehicle emissions
  C) Forest fires
  D) Industrial processes
  Show Answer
  The correct answer is B .
• Question 657:

  The emission of two successive beta particles from the nucleus ${}_{15}^{32}P$ will produce

  Options:
  A) ${}_{14}^{30}$Si
  B) ${}_{13}^{32}$Al
  C) ${}_{17}^{32}$Cl
  D) ${}_{16}^{32}$S
  Show Answer
  The correct answer is C .
• Question 658: If 100cm³ of oxygen pass through a porous plug is 50 seconds, the time taken for the same volume of hydrogen to pass through the same porous plug is? [O = 16, H = 1] Options:
  A) 10.0s
  B) 12.5s
  C) 17.7s
  D) 32.0s
  Show Answer
  The correct answer is B .
• Question 659: When temporary hard water is boiled for sometime in a kettle, the inner surface of the kettle becomes coated with a deposit of Options:
  A) calcium tetraoxosulphate(VI)
  B) calcium trioxocarbonate (IV)
  C) calcium hydrogentrioxocarbonate (IV)
  D) aluminium trioxocarbonate (IV)
  Show Answer
  The correct answer is B .
• Question 660: P1V1 = P2V2 supports ? Options:
  A) Charles’s law
  B) Boyles’s law
  C) Graham’s law
  D) Avogadro’s law
  Show Answer
  The correct answer is B .